Chicago-Latrobe
Chicago-Latrobe 44091 #21 118° Jobber Length Drill Bit
A #21 jobber-length drill bit with a 118-degree point angle made from high-speed steel and black-oxide finish
- TypeDrill Bits
- #21 size drills 0.1590 inch holes precisely
- 118° point angle starts cleanly in general materials
- High-speed steel body resists wear during repetitive drilling
- Black oxide finish reduces friction and chip welding
- Jobber length gives standard reach for bench work
Chicago-Latrobe 44091 #21 Jobber Drill Bit
The Chicago-Latrobe 44091 is a #21 jobber length drill bit made from high speed steel with a black oxide finish. It features a conventional 118 degree point angle and a decimal equivalent of .1590 inches. This general purpose bit suits maintenance professionals and metalworkers drilling wire gauge holes in steel and similar materials. It is not designed for coolant-through applications or specialised coated performance.
Thermals noise and power draw in normal use
The high speed steel construction manages heat effectively during standard drilling in mild steel and non-ferrous metals. Black oxide coating helps reduce friction and chip welding at typical hand-fed speeds. No coolant holes are present, so the bit relies on external lubrication or peck drilling to control temperature. Noise and vibration remain consistent with conventional jobber geometry in portable drills.
Behaviour under sustained load
Under continuous drilling the conventional 118 degree point maintains centring but generates more thrust than split point designs. The absence of coolant holes limits heat evacuation in deep holes, requiring frequent withdrawal to clear chips and prevent annealing. Black oxide surface treatment resists galling longer than bright finish bits, yet extended high speed runs will dull the cutting edges faster than cobalt or carbide alternatives.
Highlights
- #21 size drills 0.1590 inch holes precisely
- 118° point angle starts cleanly in general materials
- High-speed steel body resists wear during repetitive drilling
- Black oxide finish reduces friction and chip welding
- Jobber length gives standard reach for bench work
Specifications
| Brand | CHICAGO-LATROBE |
|---|---|
| Type | Drill Bits |
Questions about this item
How do I install the Chicago-Latrobe 44091 #21 drill bit correctly, and what step do people often miss?
Insert the 0.1590 inch shank fully into the chuck and tighten securely; the step often missed is verifying the bit runs true before drilling.
What maintenance or replacement will the Chicago-Latrobe 44091 #21 bit need over time?
The high-speed steel cutting edges will dull with use; resharpen the 118-degree conventional point or replace the bit when holes become oversized or rough.
What limit appears first when using the Chicago-Latrobe 44091 #21 bit continuously in tough material?
Heat buildup at the black oxide surface is the first limit; the non-coolant-through design means you must pause to let the bit cool.
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